Explanation:
Dark nebulae snake
across a gorgeous expanse of stars in
this
wide-field view
toward the
pronounceable
constellation Ophiuchus and the centre
of our Milky Way Galaxy.
In fact, the central
S-shape seen here is well known as the
Snake Nebula.
It is also listed as Barnard 72 (B72), one of 182
dark markings of the sky
catalogued in the early 20th century
by astronomer E. E. Barnard.
Unlike bright emission nebulae and star clusters,
Barnard's nebulae
are interstellar dark clouds of obscuring
gas and dust.
Their shapes are visible in
cosmic silhouette
only because they lie in the foreground along
the
line of sight to rich star fields
and glowing stellar nurseries near the plane of our Galaxy.
Many of Barnard's dark nebulae are themselves likely sites
of future star formation.
Barnard 72
is a few light years across and about 650 light years away.